Drinking water plants, manufacturing plants, irrigation systems, and power generation facilities use large quantities of water for their operation. To collect the water, screen intakes are used in various bodies of water. As shown in FIG. 1A, one common type of screen intake 10 has a tee configuration with two screens 12A-B on opposing ends of a central body 14. An outlet 16 connects from the central body 14 for connecting to components of a screen intake system.
The screen intake 10 must be designed to protect aquatic life and to prevent buildup of debris along the length of the intake's screens 12A-B. To do this, the flow velocity through the screens should be kept below a maximum peak level, which may be about 0.5 f/s. One way to reduce the flow resistance and control the flow velocity evenly across the screen's surface is to use flow modifiers inside the screen intake. For example, Johnson Screens—the assignee of the present disclosure—improves flow uniformity using flow modifiers as disclosed in U.S. Pat. Nos. 6,051,131 and 6,712,959, which are incorporated herein by reference in their entireties.
When used in a source waterway, the screen intakes 10 must be arranged with no less than a minimum amount of distance surrounding it. As shown in FIG. 1B, the standard intake 10 requires clearance above and below the screen intake 10 that is at least half of the intake's diameter. For example, a screen intake 10 having a 24-in. diameter needs 12-in. clearance above and below the intake 10 for proper operation. Thus, the 24-in. diameter screen intake 10 can mount in water with a total minimum depth of 48-in. (4-ft.).
Available source waters for intake systems are becoming shallower. For shallow applications, flat screens, velocity caps, or cribbing has been used in the past to intake source water. These traditional approaches sit flat on the bottom of the source water. Being flat, however, these types of screens can have problems with deflection and strength when subjected to flow and debris. In addition, these types of screens can be difficult to keep clear of debris. Finally, flat screens can have uneven flow distribution over the screen's surface area, which can be problematic during operation.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.